Research For Change Laws Of Soft Clay Strength And Instability Mode Of Breakwater Under Real Loading Path

In the past,the breakwater design theory and the calculation method are mostly for offshore engineering established in water area with good geological conditions;the design theory and the stability analysis method of caisson breakwater on soft clay are not mature.With the extending of coastal structures to offshore,deep-water and soft soil area,the structure safety problem of caisson breakwater on soft clay is serious.On the one hand,the overlying load applied to soil increases gradually with the gradual construction of the upper structure,on the other hand,soil consolidation degree increases because of drainage consolidation,and the structure bears the action of horizontal wave load at the same time,along with the change laws of consolidation degree and axial deviatoric stress,and the instability mode of breakwater,soft clay shear strength index under real loading path has been become a question that is concerned and needs to be solved in engineering constructions.Relying on West Port Breakwater Phrase II of Yantai Port,the paper carries out a series of researches on the change laws of soft clay shear strength and instability mode of breakwater under real loading path through static triaxial test and finite element numerical simulation.The main contents are abstracted as follow:1.Combined with the research achievements at home and abroad,considering the actual foundation soil stress state under real loading path,design and carry out the static triaxial tests which take consolidation degree and axial deviatoric stress as influencing factors,and summarize the change laws of soft clay under real loading path.2.A 3-D numerical model about caisson breakwater has been established with finite element software,and the USDFLD user subroutine is written to make material parameters about internal friction angle and cohesion with the field variable change over axial deviatoric stress in second-development platform.For the two cases with original soil strength index and considering the change of soft clay strength,finite element models of breakwater structure are calculated,and the results are compared,which clear the instability mode of breakwater under the level load or vertical load wave load and vertical load and the effects of soft clay shear strength index change on the stability of breakwater.